Recent technologies have been used to form layers of fine fiber. Fine fiber technologies that contemplate polymeric materials mixed or blended with a variety of other substances are disclosed in, for example Chung et al., U.S. Pat. No. 6,743,273. These fibers have found commercial acceptance in certain filtration applications in which a layer of fine fiber is formed on a filtration substrate. Certain of the disclosed fibers comprise an axial core comprising a phase comprising polymer materials. Surrounding the axial core can be found a layer of a coating material such as a phenolic oligomer or a fluoropolymer component.
In the formation of these fibers, a solution of the polymer and additive is formed by melt processes or electrospun to form the fiber. In certain fiber-making processes, solvents that are safe and easy to use are desired in industrial applications. Fibers formed using such solvents often need to survive and perform well in a wide variety of environments.